This invention relates to a method and apparatus for applying splicing tape to two adjacent tape ends which includes means for applying positive air pressure to the splicing tape during its application. The invention has application in processing audio or video tape, photographic film and similar products. As described below, the splicing tape may be applied by an applicator wheel which reciprocates into and out of contact with the tapes to be spliced. Means are provided which urge the splicing tape into intimate contact with the two tapes to be spliced by means of positive air pressure. The air pressure enables the splicing tape to conform to any irregularities or deformation in the two tapes to be spliced thereby creating a stronger splice.
The particular disclosure of this application is to a splicing apparatus mounted on a high-speed audio cassette winder. A standard audio cassette comprises a plastic shell within which are mounted two rotatable spools. When purchased by the user, the cassette generally has a leader attached to each spool and a length of either blank or pre-recorded magnetic tape with its two ends attached to the respective lengths of leader. One way of winding the blank or pre-recorded tape into the cassette is to begin with a cassette consisting of a shell with two spools and a single, short length of leader tape--one end connected to one spool and the other connected to the other spool. The cassette is fed into an automatic, high-speed tape winder which extracts the leader tape from the tape winder which extracts the leader tape from the tape opening in the bottom of the shell and cuts the leader tape into two separate lengths, each attached to one of the spools. One of the leaders is held momentarily while the other leader is placed on a splicing bed. The splicing bed usually comprises a trough with a somewhat greater width than that of the tape, with a longitudinally extending series of vacuum ports communicating with the bottom of the trough.
The leader is mechanically placed in the trough and held in position by suction from the ports. By one of several methods the end of the magnetic tape is manipulated into the splice bed with its free end in abutment with the end of the leader. Suction also holds the magnetic tape momentarily stationary. The exact point of abutment between the recording tape and leader end should be directly below a splicing mechanism which applies an overlapping length of splicing tape across the abutment. The spool to which the newly spliced leader is attached is then rotated at high speed, thereby winding a pre-determined length of tape onto the spool. The magnetic tape is then cut and the tail of the tape just wound onto the spool is spliced to the other end of leader which was momentarily held out of position. Any remaining slack in the tape is taken up and the cassette is ejected. Another empty cassette takes its place and the same process is repeated.
If the splice is not properly made, the leader an separate from the tape during subsequent winding or rewinding, rendering the cassette unusable. In order to ensure that the tape and leader do not separate, the adhesive splicing tape must be adequately adhered to both leader and tape. The more intimate the surface-to-surface contact, the greater stress the splice will withstand. As described above, the leader and recording tape are both held in stationary position to receive the splicing tape by means of suction on the bottom of the tapes. On conventional cassette winding machines, this suction is sufficiently strong to deform the tape downwardly somewhat, creating a number of circular depressions where the tape is drawn slightly into the individual suction ports. Since splicing tape is conventionally applied by means of impact with a metal applicator, the splicing tape is positioned flat on the splice bed. The splicing tape does not adhere to the depressions in the leader and recording tape caused by the suction ports. As a result, weak spots are created which can cause the splice to break under stress.
This problem is even more severe in the applications where suction is also used to hold the splicing tape to the tape applicator. In such cases deformation of the splicing tape occurs as well, meaning that depressions are formed by the suction on the splicing tape, causing the tape to not properly contact the leader or recording tape. Correspondingly larger weak spots are created due to the lack of intimate contact between the tapes, making separation of the splice even more likely.